Artificial finger skin having ridges and distributed tactile sensors used for grasp force control

An artificial elastic finger skin for robot fingers has been developed for controlling grasp force when weight and frictional coefficient of the grasped object are unknown. The elastic finger skin has ridges at the surface to divide the stick/slip area. It also has a pair of tactile sensors embedded per one ridge similar to human fingertips. The surface of the whole finger is curved so that reaction force distributes. A Finite Element (FE) model of the elastic finger skin was made to conduct a dynamic contact analysis using a FE method in order to design the elastic finger skin in detail. Then the elastic finger skin was made. As a result, it was confirmed by calculation and experiment that the incipient slippage of the ridge that occurs near the edge of contact area is detected. Then, a grasp force was controlled using the finger. Arbitrary object was lifted successfully by use of incipient slippage near the edge of contact area. Consequently, it was found that the artificial finger skin is useful for controlling grasping force when the weight and friction coefficient between the elastic finger skin and grasping object are unknown. 1